Brake slack adjuster



SePt- 13 1932 R. A. GoEPFRlcH BRAKE SLACK ADJUSTER Filed Feb. 25, 1929 2 Sheets-Shet 1 IN V EN TOR. @wo/p1 i @www ATTORNEY Patented Sept. ,13,1932

UNITED STATES PATENT OFFICE RUDOLPH A. GOEPFRICH, OF SOUTH BEND, INDIANA, ASSIGNOR TO BENDIX BRAKE COMPANY, OF SOUTH BEND, INDIANA, .A CORPORATION OF ILLINOIS BRAKE SLACK ADJUSTER 'Application led Fehruary 23,l 1929. Serial No. 341,891.

This invention relates to operating mechamsm for brakes or the like, and is illustrated as embodied in pedal-operated connections from the service brake pedal of`an automobile. An object of the invention isto provide simple and inexpensive means for adjusting, preferably automatically, the linkage operated by p the pedal or its equivalent, to take up any slack due to. wear or other causes.

In the drawings the invention is shown embodied, in several illustrative forms, in novel connections from the pedal `including' a ratchet-operated nut threaded on the end of the brake pull-rod, or an equivalent part. The nut is operated by a pawl mounted on thespedal and engaging a novel cam, or linked to a fixed part which operates-it when the pedal is depressed.

Various other features'relate to the structure of the nut and ratchet and to their mounting, especially to one arrangement in whic `there 1s a dierentially-threaded member giving a quicker throw to the adjustment, to a simple lcollapsible housing for the adjustment,

. adto'ther novel and desirable details which will be apparent from the following description of the .several constructions shown in the accompanying drawings, in which:

Figure 1 is a diagrammatic section of part of an automobile chassis, arrangement; j

Figure 2 is a si e elevation of the lower part of the pedalJ on a larger scale, broken away to show the adjustment;

Figure 3 is a rear elevation of the parts shown in Figure 2, looking from the right toward the left in Figure 2;

Figure 4 is a perspective of the pawloperating'cam;

Figure 5 is a view corresponding to part of Figure 2, but showing a modification including the above-mentioned dilferentially-- threaded device; Figure 6 is aside elevation of thebottom of a pedal having a somewhat diEerent type j of connection from the adjustment;

Figure 7 is a side elevatlon showing a further modification, partly broken away in section to show the structure of the adjustment;

and L showing the pedal.

. Figure 8 is a similar view of' another modification.

As shown in Figure 1, my invention is capable of use in connecting the pullrod 10, or the equivalent part, of a. brake-operating linkage to the usual service pedal or lever 12 loosely ivoted or fulcrumed on a shaft or the like 14 and projecting upwardly through the Hoorboard 16 in front of thedrivers seat 18.

In the arrangement of Figures 2-4, the pull rod 10 has a threadedpart 20 adjacent the pedal, on which is threaded a nut 22 mounted in a slot in the pedal level 12. Nut 22 is 'formed externally with a suitable operating ratchet, the teeth of which are engaged by a awl 23 in the form. of a plunger arranged 1n a housing` 2 4 secured to the pedal,so that h cam 26 keyed to the shaft 14 so that it. does not move with the pedal, by means such as a coil -spring 28 conlined between the top of. casing 24 and a stop formed on or secured to the pawl. A leaf spring 30 compressed between pawl 23 and the side of the casing not only urges the pawl against the ratchet,-

but also urges the lower end of the pawl sidewise .against the cam. In normal operation, the lower end of pawl 23 rides on a cylindrical portion or collar 32 of the cam and therefore -does not operate the nut 22. If, however, the

pedalis depressed through more than a predetermined angle, spring 30 shifts the lower end of the pawl into a notch 34 ywhich then it,` and when the pedal is released the pawl rides up on a cam surface 36 which lifts it against the resistance of'spring 28 to turn the nut 22 a distance corresponding to one ratchet tooth. The c'am`is formed with an inclined surface 38'which engages the side of the pawl at this time and which pushes the pawl. 0E the cam surface 36 when the pedal reaches its initial position, back onto the cylindrical portion 32.

In the arrangement-of Figure 5, there is threaded on part 20 an internally and externally dierentially threaded device 40 threaded into an opening in pedal 12 and formed with a' key slot 42 engaging a key on a ratchet comes opposite member 44 operated by the above-described pawl 23. n this arrangement, as the device 40 is turned by the ratchet it threads itself .axially toward the left in Figure 5, and at the same time draws part 2O toward the left"with respect to itself, thus giving part k2O a double movement whichl greatly increases its throw.

In the arrangement of Figure 6, part 2O has at its end a pin 48 riding in a curved slot 50 in a connecting arm 52 to which the pullrod 10 is pivoted and which is loosely mounted on shaft 14. The adjustment operates as described above to pull arm 52 toward the pedal 12. The pedal in this case has a closed sheet-metal socket 54 into which the` end of part 2O advances as the adjustments are made from time to time, and the exposed portion of part 20 is inclosed by a housing 56 of a helically-wound spiral of spring or resilient material such as spring steel, compressed between pedal 12 and arm 52 and collapsed gradually as the successive adjustments draw arm 52 toward pedal 12.

through the pedal and is connected by a pivot 58 to a link 60 connected by another pivot 62 to an arm 152 corresponding to arm 52. ln this case a nut 122, formed with ratchet teeth,

'is threaded on part 120 in a housing 64 secured to the pedal, 'and is operated by a pawl 123 in the form of aplunger guided in openings in the housing 64-and operated by means such as a link 66 pivoted at one end to the pawl and at the other end to a fixed part such as a chassis frame member 68.,v

In Figure 8, pedal 12 is pivoted to a housing formed as two parts 70 and 72 threaded together, and which contains a nut 222 threaded on a part 220 at the end of rod 10 and formed with ratchet teeth operated by the to those particular embodiments, or other-l wise than by the terms-of the appended claims.

'claim:

1. Operating mechanism comprising a pedal and pedal-operated vmeans and an automatically-adjustable connection therebetweenincluding, in combination therewith, a threaded member connected to said means, a nut threaded on said member and connected to the pedal, said nut having a ratchet, a pawl associated and moving with the pedal and ,engaging the ratchet, and a cam held from movement with the pedal and engaging the pawl and operated by movement of the pawl with the pedal beyond a predetermined angle to operate the pawl to move the ratchet forward one tooth.

2. Operating mechanism comprising a pedal and pedal-operated means and an automatically-adjustable connection therebetween including,in combination therewith,a threaded member connected to said means, a nut threaded on said member and connected to .the pedal, said nut having a ratchet, a pawl associated with the pedal and engaging the ratchet, and means arranged adjacent the axis of movement of the pedal and engaging the pawl and operated by movement of the pedal beyond a predetermined angle to operate the pawl to move the ratchet forward one tooth.

3.l Operating mechanism comprising, in combination, a lever, a cam adjacent the fulcrum of the lever and held from movement with the lever, operated means including a In the arrangement of Figure 7, the thread-l ed part 120, housed in a spiral 15G, passesl threaded part, a nut connected to the lever and threaded on said part and having a ratchet, a pawl engaging the ratchet-and said cam, and a spring holding the pawl yieldingly in engagement with the ratchet and cam, the cam having a part holding the pawl in a non-operable position during a predetermined throw of the lever and then permitting it to be shifted by the spring into a different position andhaving another part operatively engaging the pawl during release movement of the lever after the pawl has been so shifted and .which other part operates the pawl to shift the ratchet forward to turn the nut to take up on said operated means.

4. Operating mechanism comprising, in combination, a lever, a cam adjacent the fulcrum of the lever and held from movement with the lever, operated means including a threaded part, a nut connected to the lever and threaded on said part and having a ratchet, and a pawl engaging the ratchet and said cam and which is operated by the cam to turn the nut to take up on said operated means.

5. Uperating mechanism comprising, in combination, a lever element, an operated element, one of said elements having a thread ed part and the other having a nut threaded on said part and provided with` a ratchet, and a pawl having an actuating cam at the axis of movement of said lever element and which is arranged for opera-ting the ratchet to turn the nut when said lever is operated beyond a predetermined throw.

6.- Operating mechanism comprising, in combination, a lever, an operated element, an automatically-adjustable connection between the lever and said element, and a. housing for said connection including a compressible helically-wound spiral of resilient material.

7. Operating mechanism comprising, y combination, a lever, an operated element having a threaded part, an adjustable'nnt carriedl by the lever and threaded on sald part, a housing for said part including acompressible helically-wound splral of reslllent material surrounding said part, and a closed tubular socketinto which the end of said part advances as the nut'is operated..

8. Operating mechanism compr1s1ng, 1n

combinatiom a lever, an operated element..

having a threaded part, a nut moving with and connected to the lever and threaded on said part and provided with a ratchet, a pawl engaging the ratchet, and means for holding the lated over more than a predetermined arc.

9. Operating mechanism comprising, in

combination, a lever, any operated element l having a threaded part, a nut threaded on pawl as thelever is moved and thereby n i operate the ratchet when the lever is loscll-- between the lever and said element.

In testimony whereof, I have hereunto signed my name.

said part, automatically-operated means for turning the nut for taking up on the operated element,- and a housingv connected to the lever and enclosing the nut and said means and with said nut acting as a tension connecl tion between the .lever and sa1d.element 10. Operating -mechanism comprising, inf, `y i combination. a lever element. an operated element, both of said elements having threaded portions, an operating device having diil'erential external and internal threads engaging respectively with said threaded portions, and

means for operating said device to take up on the operated element.

11. Operating mechanism comprising, in combination. a lever element. an operated element, both of said elements having threaded portions, an operating device having differ-- enti-al external and internal threads engaging respectively with said threaded portions, a

ratchet for operating said device to take up on thel operated element, and an automati- `cally-operated pawl for actuating said ratchet.

12. Operating mechanism comprising, in combination, a lever, an operated element having a threaded part. a nut moving with and connected to the lever and threaded on said part and provided with a ratchet, a

pawl engaging the ratchet, and a tension ele- -turning the nut for taking up on the operated element, and a housing pivoted to the lever and encloslng the n ut and said means and OLPH A. GOEPFRICH.

in with said nut acting as a tension connection 

